Since the advent of central heat, homes have been heated and cooled with furnaces and air conditioning units remote to the living quarters through use of a temperature sensing unit (a "thermostat") mounted on a wall in the living area such as the living room, dining room, etc. No method exists for controlling the temperature in any room remote to the thermostated room other than setting the thermostat temperature at a higher or lower value. While some control is achieved this way, other rooms suffer too high or too low temperatures thereby incurring energy waste.
When energy costs began to rise significantly, efforts were made to reduce consumption along two fronts. In commercial establishments computerized controls were installed that interrelated demand, consumption and costs values. Specific equipment was programmed to turn on or off in relation to demand as a function involving peak utility rates to achieve the desired temperature at a lower overall cost. In homes, with one furnace and one air conditioner, such technology could not be used thus the only method of achieving reduced energy consumption was to set the temperature of the thermostat to a lower value, lower at night than during the day.
While young people can tolerate reduced warmth and lessened air conditioning, many other persons are not so fortunate. For them, a constant temperature is vitally necessary to their prolonged health and such temperature control reductions mean the onset of colds, flu and other maladies. Some effort has been made to control temperature in remote rooms by shutting off heat ducts to various unused rooms to isolate the energy system and thus reduce demand and load. The overriding problem with this procedure is that the thermostat must still be set at a fictitious temperature so that the desired temperature is achieved in the remote room and this fictitious temperature forces the energy system, i.e., the furnace, to consume unneeded and very costly energy.
The prior art is not filled with much achievement in management of home energy sytems. Attempts to date include remote controlling of furnaces using RF (radio frequency) circuitry (Isaacs, et al U.S. Pat. No. 3,605,877); remote control of furnaces using oscillator circuits controlling the magnitude of the signal as well as the energizing thereof (Machlet U.S. Pat. No. 2,764,355); superimposing an RF signal over current line to control humidifier circuit in remote area (Geister, et al U.S. Pat. No. 4,186,873); alarm for system shut down capable of interpretation between emergencies and less critical malfunctions (Henkel U.S. Pat. No. 3,007,320); superimposing pulses on the power line to actuate various energy systems within a large, multitemperature structure (Cleary, et al U.S. Pat. No. 4,132,355) and computerized systems for initial installation involving a plurality of sensors, a multiphased temperature program integrated into a pre-planned workload and controlling computer ("Energy Saver" programmable thermostat from M-C Products, Division of Material Control, Inc., 7720 E. Redfield Rd., Suite 2, Scottsdale, Ariz. 85260). All of these devices are complicated, require substantial operator knowhow and involvement, and are generally beyond the intellect and the financial means of most homeowners.
With respect to the Isaacs patent, the system is based upon providing an activation signal from a radio frequency transmitter that is coupled to a thermostat or other sensor through a first timing device, for receipt by an RF receiver on a furnace or other device to energize the furnace, the signal being adapted to be retransmitted periodically via the timer, the whole system being programmed through a second timer to shut down in the absence of the actuation signal for a set period of time. This system is monostable in that only the "on" signal or the absence of that signal causes the furnace to function. It contains no measures to filter out extraneous radiation that may hold the system in an unauthorized energized state. As the signal is merely a pulse, extraneous radiation in the form of RF pulses from a variety of sources may interfere with the operation.
The present invention is an energy management system for the homeowner that is inexpensive, easy to install and operate and provides a substantial savings in energy. It may be installed in new construction but for the most part, it is designed to be used in homes already containing a centrally located, wall-mounted thermostat or other energy level indicator. The method of achieving the desired energy savings includes shutting off energy transfer ducts to unwanted areas of the home and then utilizing a novel portable thermostat to take over control of the systems and achieve desired room temperature while holding the wall-mounted thermostat in a passive condition. Both the novel apparatus and method of using it will now provide a substantial reduction in energy consumption, while maintaining a comfortable environment for the user, commensurate with savings achieved heretofore only in the commercial community. Primary among the novel features of this invention are a coded information train, to eliminate erroneous responses due to transient radiation, a fail-safe override mechanism to phase in centralized temperature control or move to system shut-down in event of coded information pulse lapse and bistable transmission control to provide sound, accurate programming that is free from outside interference.